ISO 1268-7:2001

ISO 1268-7:2001 - Fibre-Reinforced Plastics: Resin Transfer Moulding Test Plates

Overview

ISO 1268-7:2001 specifies standardized methods for producing test plates of fibre-reinforced plastics (FRP) using the Resin Transfer Moulding (RTM) process. RTM is a closed-mould, low-pressure technique where resins are injected to impregnate fibre reinforcements within a mould cavity. This standard is part 7 of the ISO 1268 series, dedicated to defining uniform procedures allowing the production of consistent and reliable test specimens for composite material evaluation.

The standard supports material testing under internationally recognized conditions, facilitating quality control, product development, and comparison of fibre-reinforced plastics. It applies alongside ISO 1268-1 which covers general conditions for making test plates.

Key Topics

• Process Principle:
  RTM involves placing fiber reinforcements (preforms) into a mould cavity which is then closed. Resin is injected under pressure, infusing the reinforcement layers. The resin cures to form composite plates suitable for cutting into test specimens. Variations include vacuum-assisted air removal, heated resin injection to reduce viscosity, and dual-pump systems for reactive resins.

• Materials Used:

  • Reinforcements: Glass, carbon, aramid fibers in mats, rovings, woven or knitted fabrics, unidirectional fiber reinforcements, and 3D fabrics. Preforms maintain fibre alignment and provide shape before resin impregnation.
  • Resin Systems: Must have appropriate viscosity and curing behavior to fully impregnate reinforcements and produce defect-free plates.

• Plate Dimensions and Fibre Content:
  Recommended test plates typically measure 300mm x 300mm with thicknesses ranging from 1 to 4 mm. Fibre volume contents vary: 15-30% for mats, 35-55% for woven fabrics, and 40-60% for unidirectional reinforcements, optimizing mechanical property assessments.

• Equipment Requirements:
  Includes metallic or composite moulds with airtight seals, resin reservoirs with temperature control, resin injection pumps (up to 800 kPa), optional vacuum pumps, heating presses or ovens, temperature and pressure sensors, and flexible tubing connecting equipment.

• Manufacturing Procedure:

  1. Preform preparation by stacking, shaping, and bonding fibres using polymer binders, sewing, or needling.
  2. Insertion of preform into mould and secure closure.
  3. Resin injection under pressure or vacuum-assisted transfer, followed by controlled curing.
  4. Post-cure conditioning and removal of test plates.

• Quality Verification:
  Tests include measuring fibre content (ISO 1172), void content (ISO 7822), density (ISO 1183), dimensional accuracy, cure degree via differential scanning calorimetry (ISO 11357-2 & 5), and fibre alignment. Reject criteria and acceptance thresholds must be defined based on intended test use.

• Documentation:
  The standard mandates detailed reporting, including material specifications, preform configuration, moulding conditions, plate dimensions, fibre volume fraction, and test equipment used to ensure reproducibility and traceability.

Applications

ISO 1268-7:2001 is invaluable for manufacturers, researchers, and quality control laboratories involved with fibre-reinforced plastics. Its practical application ranges across:

• Composite Material R&D: Producing consistent test plates for evaluating mechanical and thermal properties.
• Quality Assurance: Ensuring batch-to-batch consistency and compliance for automotive, aerospace, marine, and sports equipment components.
• Standardized Testing: Supporting tensile, flexural, shear, and thermal measurement campaigns requiring uniform specimen preparation.
• Process Optimization: Refining RTM parameters, such as resin transfer speed, cure temperature, and fibre layout, based on reproducible plate fabrication.

Related Standards

For comprehensive composite test plate fabrication and characterization, ISO 1268-7:2001 is used alongside:

• ISO 1268-1: General conditions for producing test plates of fibre-reinforced plastics.
• ISO 1172: Glass fibre content assessment in composites.
• ISO 7822: Methods for measuring void content in reinforced plastics.
• ISO 1183: Plastic density determination.
• ISO 11357 (Parts 2 & 5): Differential scanning calorimetry for glass transition and cure analysis.

Additional parts of ISO 1268 series cover alternate manufacturing methods such as hand lay-up, compression moulding, and pultrusion, supporting varied composite production technologies.

By following ISO 1268-7:2001, stakeholders in composite manufacturing can ensure precision, reliability, and industry alignment in producing test plates via resin transfer moulding, thereby advancing composite material science and industrial application.